What is meant by a filter's "initial efficiency"?

A filter's "initial efficiency" refers to its performance rating upon installation. This measurement indicates how effectively the filter can remove particles from the air at the time it is first placed in service. It's crucial for determining how well the filter performs right when it is intended to be used, before it accumulates dust or other particulates that could affect its performance.

The initial efficiency is significant because it provides a baseline for the filter's effectiveness. Over time, as the filter captures particles, the efficiency can change, which can impact how well the system operates and the air quality provided. Understanding a filter's initial efficiency is essential for evaluating its expected performance and ensuring that it meets the intended air quality standards.

In contrast, other options like the maximum lifespan, efficiency when fully loaded, and airflow capacity pertain to different aspects of filter performance and longevity, but do not directly describe the performance metric at the moment of installation.